Compression-rubber assembly



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ATTORNEY United States Patent Chtice 3,053,478 Patented Nov. 13, 1962 3,063,478 COMPRESSEON-RUBBER ASSEMBLY William E. Wilson, East Orange, NJ., assigner to Westinghouse Electric Corporation, East Pittsburgh, Pa., a

corporation of Pennsylvania Filed June 30, 1959, Ser. No. 824,012 3 Claims. (Cl. 141-65) The present invention relates to bending machines for tubular-lamp envelopes and, more particularly, to an irnproved compression-rubber assembly for such a machine.

The linear tubular envelopes of sealed fluorescent lamps may be bent into a desired circular coniguration on a bending machine similar to the type shown in U.S. Patent No. 2,698,501, issued January 4, 1955 to S. C. Peek et al. In order to prepare the sealed fluorescent lamp for the above-mentioned bending operation the projecting end of the tubulation of such lamp is bent into a generally Z-like configuration to offset the bent end of the latter from the longitudinal axis of the lamp so that when the tubulation is mounted in a conventional compression-rubber assembly on the envelope-bending machine, such compressionrubber assembly will not project into the path of movement of the bending wheel on such machine. The conventional compression-rubber assembly may be of the type shown in U.S. Patent No. 2,254,905, issued September 2, 1941 to D. Mullan.

Compression-rubber assemblies of this type comprise essentially a body having a washer-like compression rubber seated therein and a metallic washer and a ball bearing stacked on top of the compression rubber. A cap, which is threadable on the body, has a laterally extending arm aixed thereto, which arm is precisely oriented on the cap for operative engagement with cam means on the envelope-bending machine. These cam means cause rotation of the cap to either press the metallic washer (through the ball bearing) against the compression rubber to squeeze it about the exhaust tube at the proper time, thus effecting an air tight connection therewith, or to release the pressure therefrom to facilitate insertion or withdrawal of the tubulation therefrom. The oriented arm must also be carefully oriented with respect to the path of movement of the bending wheel on the bending machine so that such arm does not interfere with the bending operation on the fluorescent lamp envelope.

ln order to load such sealed fluorescent lamp in the head of the envelope-bending machine, the open end of the bent tubulation is inserted in the rigidly mounted conventional compression-rubber assembly and the seal portions of such lamp are secured in similarly rigidly mounted envelope-holding jaws which support the lamp. Since the compression-rubber assembly and envelopeholding jaws are fixed and the pre-bent tubulation is rigid and brittle, the alignment of the end of the bent tubulation with the compression-rubber assembly is critical. Unless the alignment of the compression-rubber assembly and envelope-holding jaws is maintained in critical adjustment as well as the distance between the bent end of the tubulation and the longitudinal axis of the lamp being maintained within critical limits, it is impossible to insert the bent end of the tubulaton into the fixed compressionrubber assembly and at the same time grip the envelope in the envelope-holding jaws without breaking the tubulation.

ln addition, occasionally the tubulations break olf in the compression-rubber assembly with the result that chips or broken pieces of glass become lodged in the compression rubber thereby necessitating dismantling of the cornpression-rubber assembly to clean the latter. Further, good maintenance techniques require the periodic inspection of the compression-rubber assemblies to replace defective compression rubbers. or replace the compression rubber in the conventional compression-rubber assembly, it is necessary to first remove the cap from the body. Due to space limitations on the envelope-bending machine and the length of the oriented arm aiixed to the cap, it is impossible to remove the cap by merely rotating the oriented arm in complete revolutions until the cap is unthreaded from the body. It is therefore essential to disconnect the oriented arm from the cap before the cap may be unthreaded from the body and the ball bearing and washer removed from the body to permit the inspection, cleaning or removal of the compression rubber.

Further, the cap being small in size is often misplaced or lost after it has been removed. After the compression rubber has been inspected, cleaned or replaced, the cap is then screwed onto the body and the arm also reaxed to the body in the desired precisely oriented position, so that such arm will once more engage the above-mentioned cam means provided on the conventional envelope-bending machine. The above-described replacement operation requires the complete shut-down of the envelope-bending machine thereby resulting in considerable lost production time and maintenance cost.

From the above description of the history and defects of conventional compression-rubber assemblies on envelope-bending machines, the need for a flexible compression-rubber assembly is apparent, in order to compensate for the above-mentioned alignment problem between the bent tubulation, compression-rubber assembly and bulbholding jaws. As a first attempt to solve this problem the conventional compression-rubber assembly was replaced by a flexible piece of rubber tubing, connected to the bent tubulation and to a metallic nipple or sweep leading to the exhaust system on the envelope-bending machine. However, such rubber tubing did not provide a satisfactory hermetic seal at its juncture with the bent tubulation and at low pressures, such as l mm. of mercury, ambient air leaked into the fluorescent lamp thereby resulting in the oxidation of the heated metallic parts within the lamp (such as the cathodes and lead wires), which metallic parts are heated to a temperature of about 450 C., during the heating of the lamp envelope preparatory for the envelope-bending operation.

As a result of the oxidation of these internal lamp parts, the end portions of the lamp envelope of the finished lamp become severely darkened or blackened after about l0() hours of operation. ln addition, the bent tubulation often broke when forced into the rubber tubing.

lt is the general object of the present invention to avoid and overcome the foregoing and other difficulties of and objections to prior-art practices by the provision of an improved compression-rubber assembly which permits inspection, cleaning or replacement f such compressionrubber assembly while the envelope-bending machine is in operation.

Another object of the present invention is the provision of an improved compression-rubber assembly which reduces the maintenance time normally required for inspection, cleaning or replacement of the compression-rubber assembly and which reduces the cost of performing such inspection, cleaning or replacement operation.

A further object of the present invention is the profvision of an integral compression-rubber assembly which does not have separable component parts which can be misplaced or lost during the inspection, cleaning or replacement of the compression-rubber assembly.

Yet another object of the present invention is the provision of an improved compression-rubber assembl;I which is resilient and flexible in nature to permit connection thereof to a bent tabulation regardless of the ln order to inspect, clean4 l alignment between such compression-rubber assembly and the bent tubula'tion.

A still further object of the present invention is the provision ofvan improved compression-rubber assembly which may be readily connected in hermetic engagement with a bent tubulation without breaking the latter.

An additional object of the present invention is the provision of an improved compression-rubber assembly for an envelope-bending machine which does not interfere with the path of movement of the bending wheel during the bending of such tubular lamp envelopes into the desired arcuate configuration.

The aforesaid objects of the present invention and other objects which will become apparent as the description proceeds are achieved by providing an improved compression-rubber assembly having a hollow elastic body adapted to receive a tubulation therein and movable between a tubulation-receiving position and a tubulationsecuring position, @tbody-restraining member about the body for restraining the lateral expansion of the body while the latter is in the tubulation-securing position and a guide member in the body for preventing collapse of the body during the tubulation-inserting operation, the body being stretchable when moved from the tribulationsecuring position to the tubulan'on-receiving position so that the wall of the body is thinned out by such stretching thereby permitting the insertion of the tubulation intothe body.

For a better understanding of the present invention reference should be had to the accompanying drawings wherein like numerals of reference indicate similar parts throughout the several Views and wherein:

FIG. 1 is a side-elevational view showing a portion of the upper head of a bending machine for uorescent lamps, which head has the improved compression-rubber assembly of the present invention incorporated therein and in which assembly a bent tubulation of a linear fluorescent lamp (to be bent into a circular configuration) is secured.

FIG. 2 is an enlarged fragmentary vertical-sectional view of the loaded compression-rubber assembly taken along the line II-II of FIG. l in the direction of the arrows.

FIG. 3 is a horizontal-sectional view along the line III-III of FIG. 2 in the direction of the arrows.

FIG. 4 is a view similar to FIG. 2 but showing the position of the improved compressionqubber assembly and the upper end of the bent tu-bulation preparatory for the tubulation-loading operation.

FIG. 5 isi-a horizontal-sectional view along the line V-V of FIG. 4 in the direction of the arrows.

FIG. 6 is a View similar to FIG. 4 and showing the improved comfpressiornrubber assembly in the stretched tubulation-receiving position and the bent tubulation inserted into the guide member.

FIG. 7 is a horizontal-sectional view along the line VII-VII of FIG. 6 in the direction of the arrows.

FIG. 8 is a View similar to FIGS. 4 and 6 showing the improved compression-rubber assembly in the tubulation-securing position.

FIG. 9 is a horizontal-sectional view along the line IX-IX of FIG. 8 in the direction of the arrows.

With specific reference to the form of the present invention illustrated in the drawing and referring particularly to FIG. l, an upper head of a bending machine (similar tothe type shown in the above-mentioned U.S. Patent No. 2,698,501) is indicated generally by the reference numeral f1.

'In order to reciprocably mount the improved compression-rubber assembly of the present invention on the upper head 1, a nipple 8 (FIG. l), reciprocable by means of a handle 9 in the upper head 1, has Vits lower end inserted into an axial tubulation-receiving bore 10 (FIG. 2) of an elastic body 12 of the improved compression-rubber assembly. The upper end of the nipple 8 is connected by a flexible line 18 to a conventional lulation 22. Vbody 12 permits this registry regardless of the natural pinch clamp and valve (not shown) which controls the evacuation of the upper head '1 and the compressionrubber assembly. To secure the upper portion of the elastic body 12 to the nipple 8, such elastic body 12 is encircled by a clamp 20 whichrsqueezes such elastic body into hermetic engagement with the dependingend of the nipple 8. K

A lower portion 21 of the axial tubulation-receiving bore 19 is adapted to receive the upper end of a bent exhaust tubulation 2'2 of a linear iluorescent lamp 24 and a constricted middle portion 26 (FIGS. 4 and 6) of the axial bore 10 is adapted to Secure such upper `end of the bent exhaust tubulation 22 therein. Such axial tubulation-receiving bore 10 provides, of course, communication for exhaust purposes between Such exhaust tubulation 22 and the nipple 8.

It will be understood from a consideration of FIGS. l, 2, 4, 6 and 8 that the elastic body 12 is provided with a reduced portion 28 adjacent the tabulation-securing middle portion 26 of the bore 10, which reduced portion 28 facilitates the thinning of the Wall and the decreasing of the outside diameter of such reduced portion 28 when such elastic body 12 is stretched from the unloaded position, shown in FIG. 4, to the tubulation-receiving position shown in FIGS. 6 and 7. This reduced portion 28 is surrounded by a body-restraining ring 30, which helps constrict the adjacent tubulation-Securing middle portion 26 of the bore 10 when the elastic body 12 is in the tubulation-securing position shown in FIGS. 143. In order to prevent collapse of the lower portion 21 of the bore 10 during the stretching of the elastic body 12 from the unloaded position, shown in FIG. 4, to the tubulationreceiving position, shown in FIGS. 6 and 7, a guide sleeve 34 is positioned in such lower portion 21 of the bore 10. Such guide sleeve 34 guides the upper end of the exhaust tubulation 22 into the bore 10.

Preparatory for the tubulation-loading operation the linear fluorescent lamp 24 is secured in the upper head 1 and a lower head (not shown). The nipple 8 and compression-rubber assembly of the present invention are moved upwardly by means of the handle 9 to permit the positioning by the bending machine operator of an entrance portion 36 in the guide sleeve 34 in registry, as shown in FIG. 4, with the upper end of the bent tub- The length and resilience of the elastic alignment of the improved compression-rubber assembly and the bent exhaust tubulation 22. While holding the handle 9 in one hand, the bending-machine operator then grasps a lower portion 38 of the elastic body 12 in the other hand and stretches such elastic body from the unloaded position, shown in FIG. 4, to the tubulation-receiving position, shown in FIGS. 6 and 7, thereby thinning out the wall of the reduced portion 28 of such elastic body 12 adjacent the body-restraining ring 30 and decreasing the outside diameter of such reduced portion 28 to provide an air space 31 (FIGS. 6 and 7) between such reduced portion 28 and the body-restraining ring 30. During this stretching operation such elastic body 12 is stretched a distance d (FIG. 6), which distance d is equal to L1 (FIG. 6) -L (FIG. 4).

As a result the operator is then able to move the compression-rubber assembly downwardly from the position shown in FIG. 4, so that the exhaust tubulation 22 passes through the guide sleeve 34 to the position shown in FIG. 6, and thence into the stretched tubulation-securing middle portion 26 of the bore 10 to the position shown in FIG. 8. The above-provided air space 31 between the now-stretched reduced portion 28 and the body-restraining ring 30 permits the insertion of the upper end of the tubulation 22 into the tubulation-securing middle portion 26 without interference from the body-restraining ring 3i). The operator then releases the lower portion 38 of the elastic body 12 which resiliently moves upwardly from the tubulation-receiving position shown in FIG. 8, to the tubulation-securing position shown in FIG. 2. The resultant increase in the Wall thickness of the retracted reduced portion 28 and attendant increase in the outside diameter of such retracted reduced portion 28 eliminates the air space 31 (which had existed between the stretched reduced portion 28 and the bodyrestraining ring 30 and shown in FIG. 6) and wedges such reduced portion 28 between the upper end of the bent exhaust tubulation 22 and the -body-restraining ring 30, thereby securing the upper end of the exhaust tubulation 22 in hermetic engagement with the elastic body 12. It will be noted that because of this wedging action, a clearance 40 (FIG. 2) is provided between the top of the body-restraining ring 30 and the elastic body 12.

After the linear uorescent lamp 24 has been bent into the desired circular configuration on the bending machine, the bent exhaust tubulation 22 is tipped-off by a conventional tipping-oit mechanism (not shown) and the bent uorescent lamp 24 is then removed from the bending machine. The improved compression-rubber assembly is then stretched from the tubulation-securing position, shown in FIG. 2, to the tubulation-receiving position shown in FIG. 8 with attendant thinning of the wall of the reduced portion 28 of the elastic body 12 and resultant reduction in the outside diameter of such reduced portion 28 (to recreate the air space 31) so that the bending machine operator may readily remove the remaining portion of the exhaust tubulation 22 from the elastic body 12 preparatory for the next tubulation-loading operation at the position shown in FIG. 4.

It will be recognized by those skilled in the art that the objects of the present invention have been achieved by the provision of an improved compression-rubber assembly which permits inspection, cleaning and replacement of the subject compression-rubber assembly while the envelope-bending machine is in operation. Such improved compression-rubber assembly reduces the maintenance time normally required for the cost of inspection, cleaning or replacement of the elements of the compression-rubber assembly. In addition, the integral compression-rubber assembly of the present invention does not have separable component parts which can be misplaced or lost during the above-mentioned inspection, cleaning or replacement of the compression-rubber assembly.

Further, such improved compression-rubber assembly is resilient and exible thereby permitting its connection to a bent exhaust tubulation regardless of the alignment between compression-rubber assembly and the bent exhaust tubulation. Such improved compression-rubber assembly may be readily connected in hermetic engagement with a bent exhaust tubulation without breaking the latter and such assembly does not interfere with the path of movement of the bending wheel during bending of a tubular-lamp envelope into the desired accurate configuration.

While in accordance with the patent statutes one best known embodiment of the present invention has been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

I claim:

1 In apparatus for exhausting a fluorescent lamp through a lamp exhaust tubulation having an open end,

a compression rubber assembly for forming a hermetic seal between said exhaust tubulation and a conduit leading to an exhaust means, and means for retaining said exhaust tubulation in operative relation with respect to said compression mbber assembly; said compression rubber assembly comprising, an elongated elastic body provided with la bore extending longitudinally therethrough, one end of the bore provided through said body adapted to receive freely the open end of said exhaust tubulation, the other end of the bore provided through said body being adapted to receive the end of said conduit leading to said exhaust means, said body having a portion intermediate its ends of reduced external diameter, means for mounting one end of said body in sealing connection with said conduit, means for mounting the other end of said body, means for clampingly encompassing said intermediate body portion, said encompassing and clamping means being dimensioned to constrict said intermediate body portion so that the bore provided therethrough is smaller than the external diameter of the open end of said exhaust tubulation, and means for relatively moving said two mounting means longitudinally away from and toward each other, the movement of said two mounting means away from each other stretching said intermediate body portion against its resiliency suiicient to ermit the insertion of the open end of said exhaust tubulation into the bore provided through said intermediate body portion, and the subsequent movement of said two mounting means toward each other contracting said body portion due to its resiliency so as to sealingly engage the outer surface of the open end of said exhaust tubulation.

2. The apparatus as speciiied in claim l, wherein a rigid insert member is positioned in the end of the bore provided through said body which is adapted to receive freely the open end of said exhaust tubulation, said insert member acting to prevent collapse of said body when said two mounting means are longitudinally moved away from each other, and said insert member also facilitating guiding the open end of said exhaust tubulation into the bore provided through said body.

3. The apparatus as specied in claim 1, wherein said means for mounting said one end of said body in sealing communication with said conduit comprises a iixed member, and said means for mounting said other end of said body is normally free to permit said body to be stretched against its resilient action.

References Cited in the le of this patent UNITED STATES PATENTS 549,352 Folger Nov. 5, 1895 656,667 Schmid Aug. 28, 1900 1,600,231 Hulbert Sept. 21, 1926 1,708,141 Kepler Apr. 9, 1929 1,728,034 Bol Sept. 10, 1929 1,793,454 Bengtson Feb. 24, 1931 2,215,100 Gustin Sept. 17, 1940 2,254,905 Mullan Sept. 2, 1941 2,359,162 Sherbondy Sept. 26, 1944 2,678,761 Warren et al. May 18, 1954 2,698,501 Peek et al. Jan. 4, 1955 

